Diffusion transfer reception elements,film units and processes therefor

ABSTRACT

ZINC OXIDE IS EMPLOYED IN ASSOCIATION WITH A LIGHTREFLECTING LAYER COMPRISING TITANIUM DIOXIDE DISPERSED IN A BINDER WHICH IS ASSOCIATED WITH A DYE IMAGE-RECEIVING LAYER EMPLOYED IN COLOR DIFFUSION TRANSFER SYSTEM.

United States Patent 3,782,936 DIFFUSION TRANSFER RECEPTION ELEMENTS, FILM UNITS AND PROCESSES THEREFGR Thomas I. Abbott, Rochester, Glen M. Dappen, Webster,

and Nayyir F. Irani, Rochester, N.Y., assignors to Eastman Kodak Company, Rochester, N.Y. No Drawing. Filed Aug. 24, 1971, Ser. No. 174,443 Int. Cl. G03c 1/84, 5/54, 7/32 U.S. Cl. 96-3 22 Claims ABSTRACT OF THE DISCLOSURE Zinc oxide is employed in association with a lightreflecting layer comprising titanium dioxide dispersed in a binder which is associated with a dye image-receiving layer employed in color diffusion transfer systems.

This invention relates to the art of photography and more particularly to color diffusion transfer film units, reception elements and methods for obtaining stable, positive, right-reading diffusion transfer dye images of high quality.

U.S. Pat. 3,227,550 of Whitmore and Mader issued Jan. 4, 1966, and U.S. Pat. 3,227,552 of Whitmore issued Jan. 4, 1966, describe photographic image transfer processes wherein an immobile coupler is reacted with oxidized color developer to form a mobile dye which is transferred by diffusion to a receiving layer to form a color image. During the development phase of the color development diffusion transfer process, the image dyes formed in the respective blue-, greenand red-sensitive silver halide emulsion layers diffuse into an image-receiving layer of the receiving element where the dyes are mordanted to form the transferred image. At the same time, small amounts of development reaction products and unused color developer diffuse into the image-receiving layer. When the receiving element is separated from the photosensitive element, oxygen in the atmosphere causes rapid oxidation of the unused developer, selfcoupling of the developer occurs, thereby producing a yellowish brown stain, particularly in the highlight or minimum density areas.

U.S. Pat. 3,445,228 of Beavers et al., issued May 20, 1969, discloses that a white pigment contained in an interlayer of a dye image-receiving element for use in the above-described process conceals the stain formed in an acid layer and functions also as a timing layer. It would be desirable to provide an image-receiving element wherein higher maximum dye densities are obtainable both initially and after incubation.

Accordingly, it is an object of this invention to provide a film unit employing an image-receiving element capable of receiving stable dye images of high quality.

It is another object of this invention to provide an image-receiving element providing higher maximum dye densities of the transferred image, both initially and after subjecting to various atmospheric conditions for extended periods of time.

It is another object of this invention to provide a process of forming a transfer image employing a novel imagereceiving element.

These and other objects are achieved by a photographic film unit according to our invention, which is adapted to be processed by passing the unit between a pair of juxtaposed pressure-applying members, such as would be found in a camera designed for in-camera processing, comprising:

(a) A photosensitive element comprising a support having thereon at least one, and preferably three, photo sensitive silver halide emulsion layers, each silver halide emulsion layer having associated therewith a dye imageproviding material;

"ice

(b) A dye image-receiving layer having a light-reflecting layer associated therewith comprising titanium dioxide dispersed in a hinder, the reflecting layer having zinc oxide in association therewith; and

(c) A rupturable container containing an alkaline processing composition and which is adapted to be positioned during processing of the film unit so that a compressive force applied to the container by pressure-applying members in a camera will effect a discharge of the containers contents within the film unit.

Our invention can be used not only in diffusion transfer systems wherein the irnage-receiving element is located on a separate support from the photosensitive element, but also in diffusion transfer systems wherein the image-receiving element is integral with the photosensitive element.

In one embodiment of our invention wherein the imagereceiving element is separate from. the photosensitive element, the novel dye image-receiving element comprises a support having thereon the following layers:

(a) A light-reflecting layer comprising titanium dioxide dispersed in a binder, the light-reflecting layer having zinc oxide associated therewith, and

(b) A dye image-receiving layer.

The above-described dye image-receiving element of the film unit is adapted to be superposed on the photosensitive element after exposure thereof. The development and transfer operations can be effected by bathing either or both the exposed photosensitive element and the dye image-receiving element in a developing solution before rolling into contact with each other, or a viscous developing composition can be placed between the elements for spreading in a predetermined amount across and into contact with the exposed surface of the photosensitive element. The viscous developing composition is desirably utilized in one or more pods attached to the reception sheet or photosensitive element that can be readily ruptured when development is desired as described, for example, in U.S. Pats. 2,559,643, 2,647,049, 2,661,293, 2,698,244, 2,698,798 and 2,774,668.

During the development phase of a color diffusion transfer process according to our invention, the dye imageproviding material formed in the respective blue-, greenand red-sensitive silver halide emulsion layers diffuses out of the photosensitive element through the viscous developer composition and into the dye image-receiving layer, e.g., into the dye image-receiving element described above, where the dyes are mordanted to form the trans ferred image.

In another embodiment of our invention, the dye image-receiving layer is located integral with the photo sensitive element between the support and the lowermost photosensitive silver halide emulsion layer. Such integral receiver-negative photosensitive elements are described in copending U.S. application Ser. No. 115,459 of Barr, Bush and Thomas filed Feb. 16, 1971, now abandoned. In such an embodiment, the support for the photosensitive element is transparent and is coated with the dye imagereceiving layer, the light-reflective layer described above, and the various layers forming the color-forming units.

After exposure of the photosensitive element, a rupturable container containing an alkaline processing composition and an opaque process sheet are brought into superposed position. Pressure-applying members in a camera rupture the container and spread processing composition over the photosensitive element as the film unit is withdrawn from the camera. The processing composition develops the exposed silver halide layers and dye images are formed as a function of development which diffuse to the imagereceiving layer to provide a positive, right-reading image which is viewed through the transparent support on the opaque reflecting layer background. For further details concerning this particular integral film unit, its preparation and use, reference is made to the above-mentioned U.S. application Ser. No. 115,459 of Barr, Bush and Thomas filed Feb. 16, 1971.

Another embodiment of integral receiver-negative photosensitive systems in which our invention can be employed is described in U.S. Ser. No. 115,552 of Cole filed Feb. 16, 1971, now abandoned. In such an embodiment, the support for the color difiusion transfer system is transparent and is coated with the image-receiving layer, the lightreflective layer described above, and then the various layers forming the color-forming units and a top transparent sheet. A rupturable container containing an alkaline processing composition and an opacifier is positioned adjacent to the top layer and sheet. The film unit is placed in a camera, exposed through the top transparent sheet and then passed between a pair of pressureapplying members in the camera as it is being removed therefrom. The pressure-applying members rupture the container and spread processing composition and opacifier over the negative portion of the film unit to render it light-insensitive. The processing composition develops the exposed silver halide layers and dye images are formed as a result of development which difiuse to the imagereceiving layer to provide a positive, right-reading image which is viewed through the transparent support on the opaque reflecting layer background. For further details concerning this particular integral film unit, its preparation and use, reference is made to the above-mentioned U.S. application Ser. No. 115,552 of Cole filed Feb. 16, 1971.

The zinc oxide employed in association with the lightrefiecting layers described above may be located in the light-reflecting layer or in a separate layer contiguous thereto. It may be employed in any amount effective for the intended purpose. Generally, a concentration of from about 50 to about 500 mg./square foot of support of the dye image-receiving element will provide good results.

When the zinc oxide is employed as a separate layer or in the light-reflecting layer, it can be dispersed in any binder well-known to those skilled in the art. For example, reference is made to those described in U.S. Pat. 3,445,228 such as gelatin, polyvinyl alcohol, etc. Especially good results in certain embodiments are obtained when the binder is a vinyl polymer containing anionic solubilizing groups, as described and claimed in copending U.S. application Ser. No. 174,505 of Becker and Dappen filed of even date herewith, now U.S. Pat. No. 3,721,555 or a basic polymeric mordant as described and claimed in copending U.S. application Ser. No. 174,506 of Fix filed of even date herewith and now U.S. Pat. No. 3,721,556.

As mentioned above, the light-reflective layer employed in our invention comprises titanium dioxide dispersed in a binder. It may be employed in widely varying amounts depending upon the degree of opacity desired. The binders in which it is dispersed are the same as those mentioned above in which the zinc oxide is dispersed. Brightening agents such as the stilbenes, coumarins, triazines and oxazols can also be added, if desired. It is believed that any stain resulting from excess developing agent or oxidized developing agent is hidden in or masked by this layer.

When a pH-lowering layer is employed, such as a polymeric acid layer, the light-reflecting layer will function as a timing layer and will control the pH reduction of the dye image-receiving element as a function of the rate at which the alkali diffuses through the layer.

The film assembly of our invention can be used to produce positive images in singleor multicolors. In a three-color system, each silver halide emulsion layer of the film assembly of our invention will have associated therewith a dye image-providing material possessing a spectral absorption range substantially complementary to the pr dominant se sitiv y r g f t associated emulsion, i.e., the blue-sensitive silver halide emulsion layer will have a yellow dye image-providing material associated therewith, the green-sensitive silver halide emulsion layer will have a magenta dye image-providing material associated therewith, and the red-sensitive silver halide emulsion layer will have a cyan dye image-providing material associated therewith. The dye image-providing material associated with each silver halide emulsion layer can be contained either in the silver halide emulsion layer itself or in a layer contiguous to the silver halide emulsion layer.

Spectral sensitizing dyes can be used conveniently to confer additional sensitivity to the light sensitive silver halide emulsion of the multilayer photographic elements of the invention. For instance, additional spectral sensitization can be obtained by treating the emulsion with a solution of a sensitizing dye in an organic solvent or the dye may be added in the form of a dispersion as described in Owens et al. British Pat. 1,154,781 issued June 11, 1969. For optimum results, the dye can either be added to the emulsion as a final step or at some earlier stage.

Sensitizing dyes useful in sensitizing such emulsions are described, for example, in Brooker et al., U.S. Pat. 2,526,632, issued Oct. 24, 1950; Sprague U.S. Pat. 2,503,776, issued Apr. 11, 1950; Brooker et a1. U.S. Pat. 2,493,748, issued Jan. 10, 1950; and Taber et al., U.S. Pat. 3,384,486 issued May 21, 1968. Spectral sensitizers which can be used include the cyanines, merocyanines, complex (tri or tetranuclear) merocyanines, complex (tri or tetranuclear) cyanines, holopolar cyanines, styryls, hemicyanines (e.g. enamine hemicyanines), oxonols and hemioxonols. Dyes of the cyanine classes can contain such basic nuclei as the thiazolines, oxazolines, pyrrolines, pyridines, oxazoles, thiazoles, selenazoles and imidazoles. Such nuclei can contain alkyl, alkylene, hydroxyalkyl, sulfoalkyl, carboxyalkyl, aminoalkyl and enamine groups and can be fused to carbocyclic or heterocyclic ring systems either unsubstituted or substituted with halogen, phenyl, alkyl, haloalkyl, cyano, or alkoxy groups. The dyes can be symmetrical or unsymmetrical and can contain alkyl, phenyl, enamine or heterocyclic substituents on the methine or polymethine chain. The merocyanine dyes can contain the basic nuclei mentioned above as well as acid nuclei such as thiohydantoins, rhodanines, oxazolidenediones, thiazolidenediones, barbituric acids, thiazolineones, and malononitrile. These acid nuclei can be substituted with alkyl, alkylene, phenyl, carboxyalkyl, sulfoalkyl, hydroxyalkyl, alkoxyalkyl, alkylamino groups, or heterocyclic nuclei. Combinations of these dyes can be used, if desired. In addition, supersensitizing addenda which do not absorb visible light can be included, for instance, ascorbic acid derivatives, azaindenes, cadmium salts, and organic sulfonic acids as described in McFall et al. US. Pat. 2,933,390 issued Apr. 19, 1960 and Jones et al. U.S. Pat. 2,937,089 issued May 17, 1960.

The various silver halide emulsion layers of a color film assembly of the invention can be disposed in the usual order, i.e., the blue-sensitive silver halide emulsion layer first with respect to the exposure side, followed by the green-sensitive and red-sensitive silver halide emulsion layers. If desired, a yellow dye layer or a Carey Lea silver layer can be present between the blue-sensitive and green-sensitive silver halide emulsion layer for absorbing or filtering blue radiation that may be transmitted through the blue-sensitive layer. If desired, the selectively sensitized silver halide emulsion layers can be disposed in a different order, e.g., the blue-sensitive layer first with respect to the exposure side, followed by the red-sensitive and green-sensitive layers.

The silver halide emulsions used in this invention can comprise, for example, silver chloride, silver bromide, silver chlorobromide, silver bromoiodide, silver chlorobromoiodide or mixtures thereof. The emulsions can be coarse or fine grain and can be prepared by any of the well-known procedures, e.g., single jet emulsions such as those described in T rivelli and Smith, The Photographic Journal, vol. LXXIX, May 1939 (pp. 330-338), double jet emulsions, such as Lippmann emulsions, ammoniacal emulsions, thiocyanate or thioether ripened emulsions such as those described in Nietz et al. US. Pat. 2,222,264 issued Nov. 19, 1940; Illingsworth U. S. Pat. 3,320,069 issued May 16, 1967; and McBride US. Pat. 3,271,157 issued Sept. 6, 1966. Surface image emulsions can be used or internal image emulsions can be used such as those described in Davey et al. US. Pat. 2,592,250 issued May 8, 1952; Porter et al. US. Pat. 3,206,313 issued Sept. 14, 1965; Berriman US. Pat. 3,367,778 issued Feb. 6, 1968; and Bacon et al. US. Pat. 3,447,927 issued June 3, 1969. The emulsions may be regular grain emulsions such as the type described in Klein and Moisar, I. Phot. Sci., vol. 12, No. 5, September/ October 1964 (pp. 242-251). Negative type emulsions may be used or direct positive emulsions may be used such as those described in Leermakers US. Pat. 2,184,013 issued Dec. 19, 1939; Kendall et al. U.S. Pat. 2,541,472 issued Feb. 13, 1951; Berriman US. Pat. 3,367,778 issued Feb. 6, 1968; Schouwenaars British Pat. 723,019 issued Feb. 2, 1955; Illingsworth et al. French Pat. 1,520,821 issued Mar. 4, 1968; Illingsworth US. Pat. 3,501,307 issued Mar. 17, 1970; Ives US. Pat. 2,563,785 issued Aug. 7, 1951; Knott et al. US. Pat. 2,456,953 issued Dec. 21, 1948; and Land US. Pat. 2,861,885 issued Nov. 25, 1958.

The emulsions used with this invention may be sensitized with chemical sensitizers, such as With reducing agnts; sulfur, selenium or tellurium compounds; gold, platinum or palladium compounds; or combinations of these. Suitable procedures are described in Sheppard et al. US. Pat. 1,623,499 issued Apr. 5, 1927; Waller et al. US. Pat. 2,399,083 issued Apr. 23, 1946; McVeigh U.S. Pat. 3,297,447 issued Jan. 10, 1967; and Dunn US. Pat. 3,297,446 issued Jan. 10, 1967.

The silver halide emulsions used with this invention may contain speed increasing compounds such as polyalkylene glycols, cationic surface agents and thioethers or combinations of these as described in Piper US. Pat. 2,886,437 issued May 12, 1959; Dann et a1. U.S. Pat. 3,046,134 isued July 24, 1962; Carroll et al. US. Pat. 2,944,900 issued July 12, 1960; and Goffe US. Pat. 3,294,- 540 issued Dec. 27, 1966.

The silver halide emulsions used in the practice of this invention can be protected against the production of fog and can be stabilized against loss of sensitivity during keeping. Suitable antifoggants and stabilizers each used alone or in combination include thiazolium salts described in Brooker et al. US. Pat. 2,131,038 issued Sept. 27, 1938; and Allen et al. US. Pat. 2,694,716 issued Nov. 16, 1954; the azaindenes described in Piper US. Pat. 2,886,437 issued May 12, 1959; and Heimbach et al. US. Pat. 2,444,605 issued July 6, 1948; the mercury salts as de scribed in Allen et al. US. Pat. 2,728,663 issued Dec. 27, 1955; the urazoles described in Anderson et al. US. Pat. 3,287,135 issued Nov. 22, 1966; the sulfocatechols described in Kennard et al. US. Pat. 3,236,652 issued Feb. 22, 1966; the oximes described in Carroll et al. British Pat. 623,448 issued May 1-8, 1949; nitron; nitroindazoles; the mercaptotetrazoles described in Kendall et al. US. Pat. 2,403,927 issued July 16, 1946; Kennard et al. US. Pat. 3,266,897 issued Aug. 16, 1966; and Luckey et al. US. Pat. 3,397,987 issued Aug. 20, 1968; the polyvalent metal salts described in Jones US. Pat. 2,839,405 issued June 17, 1958; the thiuronium salts described in Herz et al. US. Pat. 3,220,839 issued Nov. 30, 1965; the palladium, platinum and gold salts described in Trivelli et al. US. Pat. 2,566,263 issued Aug. 28, 1951; and Yutzy et al. US. Pat. 2,597,915 issued Ma 27, 1952; and the tetrazoles described in Hoppe US. Pat. 3,352,672 issued Nov. 14, 1967.

Any dye image-providing material can be employed in this invention as long as an imagewise distribution of the material will be formed after development as a function of the imagewise exposure of the silver halide emulsion to which the dye image-providing material is associated. For example, there may be employed as the dye imageproviding material dye developers as illustrated by US. Pat. 2,983,606; coupling dyes as disclosed, for example, in US. Pat. 3,087,817; shifted or leuco dye developers; dye developer precursors; metal dye complexes as dis closed, for example, in US. Pat. 3,185,567 and 3,453,107;

couplers requiring an oxidizing agent in the image-receiv- DYE-LINK-(COUP-BALL) and BALL-LINK-(COUB-SOL) wherein (1) DYE is a dye radical exhibiting selective absorption in the visible spectrum and containing an acidic solubilizing radical;

(2) LINK is a connecting radical such as an azo radical, a mercuri radical, an oxy radical, an alkylidene radical, a thio radical, a dithio radical or an azoxy radical;

(3) COUP is coupler radical such as a S-pyrazolone coupler radical, a pyrazolotriazole coupler radical, a phenolic coupler radical or an open-chain ketomethylene coupler radical, COUP being substiuted in the coupling position with LINK;

(4) BALL is a photographically inert organic ballasting radical of such molecular size and configuration as to render such coupler nondiifusible during development in the alkaline processing composition;

(5) SOL is a hydrogen atom or an acidic solubilizing group when the color developing agent contains an acidic solubilizing group, and SOL is an acidic solubilizing group when the color developing agent is .free of and acidic solubilizing group; and

(6) n is an integer of 1 to 2 when LINK is an alkylidene radical, and n is 1 when LINK is an azo radical, a mercuri radical, an oxy radical, a thio radical, a dithio radical or an azoxy radical.

For further details concerning the above-described couplers, their preparation and use, reference is made to US. Pat. 3,227,550 of Whitmore et al.. issued Jan. 4, 1966; US. Pat. 3,227,552 of Whitmore issued I an. 4, 1966; and British Pat. 904,364, p. 19, lines 1-41.

If the silver halide emulsion employed with the nondiifusible couplers described above is a direct-positive silver halide emulsion, such as an internal-image emulsion or a solarizing emulsion, which is developable in unexposed areas, a positiveimage can be obtained on the dye imagereceiving layer. In this embodiment, the nondiffusible coupler can be located in the silver halide emulsion itself. After exposure of the film unit, the alkaline processing composition permeates the various layers to initiate development of the exposed photosensitive silver halide emulsion layers. The aromatic primary amino color developing agent present in the film unit develops each of the silver halide emulsion layers in the unexposed areas (since the silver halide emulsions are direct-positive ones), thus causing the developing agent to become oxidized imagewise corresponding to the unexposed areas of the directpositive silver halide emulsion layers. The oxidized developing agent then reacts with the nondiftusible coupler present in each silver halide emulsion layer to form imagewise distributions, respectively, of diffusible cyan, magenta and yellow dye as a ,function of the imagewise exposure of each of the silver halide emulsion layers. At least a portion of the imagewise distributions of diifusible cyan, magenta and yellow dye difliuse to the image-receiving layer to provide a positive dye image upon separation of the receiver from the negative.

Internal-image silver halide emulsions useful in the above-described embodiment are direct-positive emulsions that form latent images predominantly inside the silver halide grains, as distinguished from silver halide grains that form latent images predominantly on the surface thereof. Such internal-image emulsions were described by Davey et al. in U.S. Pat. 2,592,250 issued Apr. 8, 1952, and elsewhere in the literature. These emulsions can also contain fogging or nucleating agents such as those described in U.S. Pat. 2,588,982; 2,563,785; 3,227,552; etc.

As previously mentioned, the aromatic primary amino color developing agent employed in the above-described embodiment is preferably present in the alkaline processing composition in the rupturable pod. The color developing agent can also be incorporated into the negative portion of the film unit as a separate layer, e.g., by employing a Schiif base derivative of an aromatic primary amino color developing agent such as that formed by reacting o-sulfobenzaldehyde and N,N-diethyl-3-methyl-4-aminoaniline. Such incorporated developing agent will be activated by the alkaline processing composition. While the incorporated developing agent can be positioned in any layer of the photosensitive element from which it can be readily made available for development upon activation with alkaline processing composition, it is generally either incorporated in the light-sensitive silver halide emulsion layers or in layers contiguous thereto. As mentioned above, aromatic primary amino color developing agents employed in certain embodiments of this invention are preferably p-phenylenediamine developing agents. These developing agents are well-known to those skilled in the art and include the following compounds and salts thereof:

4-amino-N,N-diethyl-3-methyl aniline, N,N-diethyl-p-phenylenediamine, N-ethyl-p-methanesulfonamideoethyl-3-methyl-4- aminoaniline, 4-amino-N-ethyl-3 -methyl-N- ,B-sulfoethyl) aniline, 4-amino-N-ethyl-3-methoxy-N- B-sulfoethyl) aniline, 4-amino-N-ethyl-N- ("B-hydroxyethyl aniline, 4-aminoN,N-diethyl-3-hydroxymethyl aniline, 4-amino-N-methyl-N-(B-carb'oxyethyl) aniline, 4-amino-N,N-bis(fl-hydroxyethyl) aniline, 4-amino-N,N-bis( e-hydroxyethyl -3-methyl aniline, 3 -acetamido-4-amino-N,N-bis fl-hydroxyethyl) aniline, 4-amino-Nethyl-N- 2,3-dihydroxypropyl) -3-methyl aniline, 4-amino-N,N-diethyl-3-(3-hydroxypropoxy) aniline, and the like.

In a color film unit according to the invention, each silver halide emulsion layer containing a dye image-providing material or having the dye image-providing material present in a contiguous layer may be separated from the other silver halide emulsion layers in the negative portion of the film unit by materials in addition to those described above, including gelatin, calcium alginate, or any of those disclosed in U.S. Pat. 3,3 84,483, polymeric materials such as polyvinylamides as disclosed in US. Pat. 3,421,892, or any of those disclosed in U.S. Pat. 2,992,104, 3,043,692, 3,044,873, 3,061,428, 3,069,263, 3,069,264, 3,121,011 and 3,427,158.

Generally speaking, except where noted otherwise, the silver halide emulsion layers in the invention comprise photosensitive silver halide dispersed in gelatin and are about 0.6 to 6 microns in thickness; the dye image-providing materials are dispersed in an aqueous alkaline solunon-permeable polymeric binder, such as gelatin, as a separate layer about 1 to 7 microns in thickness; and the alkaline solution-permeable polymeric interlayers, e.g., gelatin, are about 1 to 5 microns in thickness. Of course, these thicknesses are approximate only and can be modified according to the product desired. In addition to gelatin, other suitable hydrophilic materials include both naturally occurring substances such as proteins, cellulose derivatives, polysaccharides such as dextran, gum arabic and the like; and synthetic polymeric substances such as water-soluble polyvinyl compounds like poly(vinylpyrrolidone) acrylarnide polymers and the like.

The photographic emulsion layers and other layers of a photograhpic elment employed in the practice of this invention can also contain alone or in combination with hydrophilic, water-permeable colloids, other synthetic polymeric compounds such as dispersed vinyl compounds such as in latex form and particularly those which increase the dimensional stability of the photographic materials. Suitable synthetic polymers include those described, for example, in Nottorf, U.S. Pat. 3,142,568 issued July 28, 1964; White, U.S. Pat. 3,193,386 issued July 6, 1965; Houck et al., U.S. Pat. 3,062,674 issued Nov. 6,

1962; Hock et al., U.S. Pat. 3,220,844 issued Nov. 30, 1965; Ream et al., U.S. Pat. 3,287,289 issued Nov. 22, 1966; and Dykstra, U.S. Pat. 3,411,911 issued Nov. 19, 1968. Particularly eifective are water-insoluble polymers of alkyl acrylates and methacrylates, acrylic acid, sulfoalkyl acrylates or methacrylates, those which have crosslinking sites which facilitate hardening or curing described in Smith, U.S. Pat. 3,488,708 issued Jan. 6, 1970, and those having recurring sulfobetaine units as described in Dykstra, Canadian Pat. 774,054.

Any material can be employed as the image-receiving layer in this invention as long as the desired function of mordanting or otherwise fixing the dye images will be obtained. The particular material chosen will, of course, depend upon the dye to be mordanted. If acid dyes are to be mordanted, the image-receiving layer can contain basic polymeric mordants such as polymers of amino guanidine derivatives of vinyl methyl ketone such as described in Minsk U.S. Pat. 2,882,156 issued Apr. 14, 1959, and basic polymeric mordants such as described in U.S. Pat. No. 3,709,690 of Cohen et al. issued J an. 9, 1973. Other mordants useful in our invention include poly-4-vinylpyridine, the 2-vinyl pyridine polymers metho-p-toluene sulfonate and similar compounds described in Sprague et al. U.S. Pat. 2,484,430 issued Oct. 11, 1949, and cetyl trimethylammonium bromide, etc. Effective mordanting compositions are also described in Whitmore U.S. Pat. 3,271,148 and Bush US. Pat. 3,271,147, both issued Sept. 6, 1966.

Furthermore, the image-receiving layer can be sufiicient by itself to mordant the dye as in the case of use of an alkaline solution-permeable polymeric layer such as N-methoxy-methyl polyhexamethylene adipamide; partially hydrolyzed polyvinyl acetate; polyvinyl alcohol with or without plasticizers; cellulose acetate; gelatin; and other materials of a similar nature. Generally, good results are obtained when the image-receiving layer, preferably alkaline solution-permeable, is transparent and about 0.25 to about 0.40 mil in thickness. This thickness, of course, can be modified depending upon the result desired. The image-receiving layer can also contain ultra-violet absorbing materials to protect the mordanted dye images from fading due to ultraviolet light, brightening agents such as the stilbenes, coumarins, utriazines, oxazoles, dye stabilizers such as the chromanols, alkylphenols, etc.

Use of a pH-lowering material associated with the dye image-receiving element of the invention will usually increase the stability of the transferred image. Generally, the pH-lowering material Will effect a reduction in the pH of the image layer from about 13 and 14 to at least 11 and preferably 5-8 within a short time after imbibition. For example, polymeric acids as disclosed in U.S. Pat. 3,362,819; or metallic salts, e.g., zinc acetate, zinc sulfate, magnesium acetate, the formates, acetates, propionates, stearates, nitrates, or sulfates of zinc, aluminum, iron, manganese, cobalt or nickel, etc.; or solid acids as disclosed in U.S. Pat. 2,584,030 may be employed with good results. Such pH-lowering materials reduce the pH of the film unit after development to terminate development and substantially reduce further dye transfer and thus stabilize the dye image. The pH-lowering material can be present as a separate layer between the light-reflecting layer and its support where the image-receiving element is separate from the photosensitive element or can be located between the light-reflecting layer and the lowermost silver halide emulsion layer in an integral receivernegative element.

The alkaline processing composition employed in this invention is the conventional aqueous solution of an alkaline material, e.g., sodium hydroxide, sodium carbonate or an amine such as diethylamine, preferably possessing a pH in excess of 12. The solution also preferably contains a viscosity-increasing compound such as a high-molecularweight polymer, e.g., a water-soluble ether inert to alkaline solutions such as hydroxyethyl cellulose or alkali metal salts of carboxymethyl cellulose such as sodium canboxymethyl cellulose. A concentration of viscosity-increasing compound of about 1 to about 5% by weight of the processing solution is preferred which will impart thereto a viscosity of about 100 cps. to about 200,000 cps.

While the alkaline processing composition used in this invention can be employed in a rupturable container, as described previously, other methods of applying processing composition could also be employed, e.g., bathing the photosensitive element in a processing bath, interjecting processing composition with communicating members similar to hypodermic syringes which are attached either to a camera or camera cartridge.

While the film units of our invention can be modified so as to be employed in roll form, they are preferably used in cartridges similar to those described in U.S. Pats. 3,080,- 805, 3,161,118 and 3,161,122, said patents also illustrating typical cameras for performing color difi'usion transfer processes of our invention.

The supports for the photographic elements of this invention can be any material as long as it does not deleteri ously affect the photographic properties of the film unit and is dimensionally stable. Typical materials include cellulose nitrate film, cellulose acetate film, poly(vinyl acetal) film, polystyrene film, poly(ethyleneterephthalate) film, polycarbonate film, poly-a-olefins such as polyethylene and polypropylene film, and related films or resinous materials, as well as glass, paper, metal, etc. The support is usually about 2 to 6 mils in thickness.

The dye image-receiving element of our invention can be prepared by employing various leveling agents and/ or coating aids such as the copolymers of dimethyl siloxane and polyoxyalkylene ether described in U.S. Pats. 3,324,- 058 and 3,483,240. The dye image-receiving element according to our invention can also be overcoated with a hydrophilic colloid layer such as gelatin, gum arabic or any of those materials described in U.S. application Ser. No. 100,486 of Abbott filed Dec. 21, 1970. In addition, the dye image-receiving element of our invention can contain ultraviolet absorbing materials to protect the mordanted dye images from fading due to ultraviolet light. Such materials are described in U.S. Pats. 3,460,942; 3,069,262; 3,330,680 and 3,330,656.

The photographic layers employed in the practice of this invention may contain surfactants such as saponin or any of the materials described in U.S. Pats. 2,600,831; 3,133,816; or 3,514,293 or British Pat. 1,022,878.

The various layers, including the photographic layers, employed in the practice of this invention can contain light absorbing materials and filter dyes such as those described in Sawdey U.S. Pat. 3,253,921 issued May 31, 1966; Gaspar U.S. Pat. 2,274,782 issued Mar. 3, 1942;

10 Silberstein et al. U.S. Pat. 2,527,583 issued Oct. 31, 1950; and Van Campen U.S. Pat. 2,956,879 issued Oct. 18, 1960.

The sensitizing dyes and other addenda used in the practice of this invention can be added from water solutions or suitable organic solvent solutions may be used. The compounds can be added during various procedures including those described in Collins: et al. U.S. Pat. 2,912,- 343 issued Nov. 10, 1959; McCrossen et a1. U.S. Pat. 3,342,605 issued Sept. 19, 1967; Audran U.S. Pat. 2,996,- 287 issued Aug. 15, 1961 and Johnson et al. U.S. Pat. 3,425,835 issued Feb. 4, 1969.

The photographic layers used in the practice of this invention may be coated by various coating procedures including dip coating, air knife coating, curtain coating, or extrusion coating using hoppers of the type described in Beguin U.S. Pat. 2,681,294 issued June 15, 1954. If desired, two or more layers may be coated simultaneously by the procedures described in Russell U.S. Pat. 2,761,791 issued Sept. 4, 1956; Hughes U.S. Pat. 3,508,947 issued Apr. 28, 1970; and Wynn British Pat. 837,095 issued June 9, 1960. This invention also can 'be used for silver halide layers coated by vacuum evaporation as described in British Pat. 968,453 issued Sept. 2, 1964 and Lu Valle et al. U.S. Pat. 3,219,451 issued Nov. 23, 1965.

The photographic and other hardenable layers used in the practice of this invention can be hardened by various organic or inorganic hardeners, alone or in combination, such as the aldehydes, and blocked aldehydes as described in Allen et al. U.S. Pat. 3,232,764 issued Feb. 1, 1966; ketones, carboxylic and carbonic acid derivatives, sulfonate esters, sulfonyl halides and vinyl sulfonyl ethers as described in Burness et al. U.S. Pat. 3,539,644 issued Nov. 10, 1970; active halogen compounds, epoxy compounds, aziridines, active olefins, isocyanates, carbodiimides, polymeric hardeners such as oxidized polysaccharides like dialdehyde starch and oxyguargum and the like.

The following examples further illustrate the invention.

EXAMPLE 1 Five dye image-receiving elements are prepared by coating the following layers in the order recited on a polyethylene-coated paper support:

(1) polymeric acid layer of poly(methyl vinyl ether/ maleic anhydride) (825 mg./ft.

(2) light-reflecting layer of copoly[styrene-N-benzyl-N,

N-dimethyl-N-(3 maleimidopropyl)ammonium chloride] (400 mg./ft. titanium dioxide (1000 mg./ft. and zinc oxide (amounts listed in Table 1);

(3) mordant layer of copoly[styrene-N-benzyl-N,N-dimethyl-N-(3 ma-leimidopropyl)ammonium chloride] (200 mg./ft. and gelatin (200 mg./ft. and

(4) overcoat layer of gelatin (4'0 mg./ft. and gum arabic (20 mg./ft.

A multicolor photographic element of the type described in Example 1 of Whitmore et al., U.S. Pat. 3,227,- 550 issued Jan. 4, 1966, is prepared. The emulsions are direct-positive, gelatino, silver bromoiodide emulsions containing cyan, magenta and yellow dye-forming couplers in the red, green and blue light-recording emulsions, respectively. 4

Samples of the above photosensitive element are exposed to a multicolor test object. The following processing composition is spread from a pod between the exposed surface of each element and the superposed imagereceiving element described above by passing the transfer sandwich between a pair of juxtaposed pressure rollers:

Potassium hydroxide 35.0 4-amino-N-ethyl-N-fi-hydroxyethyl aniline 40.0 5-methylbenzimidazole 0.02 Hydroxyethyl cellulose 30.0 Water to 1 liter.

1 1 After 60 seconds at about 20 C., each dye image-receiving element is peeled apart from. the negative. The minimum and maximum densities to red, green and blue are then measured, both fresh and after 7 days at 140 F./70% relative humidity. The following results are obtained:

ing thereon at least one photosensitive silver halide emulsion layer, each said silver halide emulsion layer having associated therewith a dye image-providing material;

(b) a dye image-receiving layer having a light-reflecting layer associated therewith comprising titanium TABLE 1 Fresh 7 days at 140 F./70% R.H.

min mnx. m u. max. Amount of zinc oxide in light-refleeting layer (mg/ft?) Red Green Blue Red Green Blue Red Green Blue Red Green Blue The above results indicate the improvements in D keeping stability which is obtained in accordance with our invention without affecting the D EXAMPLE 2 In order to compare the use of zinc oxide with other prior-art materials, the following dye image-receiving elements are prepared by coating the following layers in the order recited on a polyethylene-coated paper support:

(1) polymeric acid layer of poly(methyl vinyl ether/ maleic anhydride) (825 mg./ft.

(2) light-reflecting layer of copoly[styrene-N-benzyl-N,

N-dimethyl-N-(3 maleimidopropyl)ammonium chloride] (300 mg./ft. and titanium dioxide (1000 mg./ ft.

(3) light-reflecting layer of copoly[styrene-N-benzyl-N,

N-dimethyl-N-(3 maleirnidopropyl)ammonium chloride] (100 mg./ft. and the compounds listed in Table (4) mordant layer of copoly[styrene-N-benzyl-N,N-dimethyl-N-(3 maleimidopropyl)ammonium chloride] (200 mg./ft. and gelatin (200 mg./ft. and

() overcoat layer of gelatin (40 mg./ft. and gum arabic mg./ft.

The above dye image-receiving elements are then tested according to the same procedure described in Example 1. The maximum densities to red, green and blue are then measured, both fresh and after 7 days at 140 F./ 70% relative humidity. The following results are obtamed:

TABLE 2 mux 7 days at Compound in It ght- Dmnx. FI'0Sh 140 F./70% RH. reflecting layer (3) (mg/1L Red Green Blue Red Green Blue N0ne 1. 59 1. 56 1. 64 1. 38 1. 38 0.87 Magnesium oxide (50). 1. 65 1. 50 1. 81 1. 54 1. 48 1.38 Magnesium oxide (100) 1. 63 1. .54 1. 78 1. 53 1. 46 1. 36 Calcium oxide (50)...- 1. 69 1. 65 2.01 1.42 1. 40 1. 04 Zinc oxide (50) 2.19 2. 08 1. 96 2.20 2.12 1. 93 Zinc oxide (100) 2.03 2.03 1. 93 2. 24 2. 16 1. 94 Zinc oxide (200) 2. 33 2. 18 2. 02 2. 18 2. 14 1. 94 Zinc oxide (400) 2.04 1. 02 1. 77 2. 10 2.02 1. 88

The above results illustrate the superiority of zinc oxide in comparison to magnesium oxide and calcium oxide when used in combination with titanium dioxide in a dye image-receiving element according to our invention.

The invention has been described with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

We claim:

1. In a photographic film unit which is adapted to be processed by passing said unit between a pair of juxtaposed pressure-applying members comprising:

(a) a photosensitive element comprising a support havdioxide in a binder; and (c) a rupturable container containing an alkaline processing composition and which is adapted to be positioned during processing of said film unit so that a compressive force applied to said container by said pressure-applying members will effect a discharge of the containers contents within said film unit; the improvement comprising employing zinc oxide in association with said light-reflecting layer.

2. The photographic film unit of claim 1 wherein said photosensitive element comprises a support having thereon a red-sensitive silver halide emulsion layer having associated therewith a cyan dye image-providing material comprising a nondiifusible coupler capable of reacting with oxidized aromatic primary amino color developing agent to produce a diifusible cyan dye, a green-sensitive silver halide emulsion layer having associated therewith a magenta dye image-providing material comprising a nondiffusible coupler capable of reacting with oxidized aromatic primary amino color developing agent to produce a diifusible magenta dye, and a blue-sensitive silver halide emulsion layer having associated therewith a yellow dye image-providing material comprising a nondiifusible coupler capable of reacting with oxidized aromatic primary amino color developing agent to produce a diffusible yellow dye; said film unit containing an aromatic primary amino color developing agent.

3. The film unit of claim 1 wherein said dye imagereceiviug layer is located in said photosensitive element between said support and the lowermost photosensitive silver halide emulsion layer, and said light-reflecting layer is located in said photosensitive element between said dye image-receiving layer and said lowermost photosensitive silver halide emulsion layer.

4. The film unit of claim 1 wherein said dye imagereceiving layer is coated on a separate support and is adapted to be superposed on said photosensitive element after exposure thereof, and said light-reflecting layer is located between said dye image-receiving layer and its said support.

5. The film unit of claim 4 wherein said rupturable container is so positioned during processing of said film unit that a compressive force applied to said container by said pressure-applying members will effect a discharge of the containers contents between said dye image-receiving layer and the outermost layer of said photosensitive element.

6. The film unit of claim 1 which also contains a pH- lowering material.

7. The film unit of claim 1 wherein said zinc oxide is present in said light-reflecting layer.

8. The film unit of claim 1 wherein said zinc oxide is present in a layer contiguous to said light-reflecting layer.

9. The film unit of claim 1 wherein said zinc oxide is present at a concentration of from about 25 to about 500 mg./ft.

3 10. In a photographic film unit which is adapted to be processed by passing said unit between a pair of juxtaposed pressure-applying members comprising:

(I) a photosensitive element comprising a support having thereon the following layers in sequence:

(a) a direct-positive, red sensitive silver halide emulsion layer containing a nondifi'usible coupler capable of reacting with oxidized aromatic primary amino color developing agent to produce a dilfusible cyan dye;

(b) an alkaline solution-permeable interlayer containing a compound capable of scavenging oxidized aromatic primary amino color developing agent;

() a direct-positive, green-sensitive silver halide emulsion layer containing a nondiifusible coupler capable of reacting with oxidized aromatic primary amino color developing agent to produce a difiusible magenta dye;

(d) an alkaline solution-permeable interlayer containing a compound capable of scavenging oxidized aromatic primary amino color developing agent; and

(e) a direct-positive, blue-sensitive silver halide emulsion layer containing a nonditfusible coupler capable of reacting with oxidized aromatic primary amino color developing agent to produce a diffusible yellow dye;

each said nondiffusible coupler having the formula:

DYE-LINK- COUP-BALL) n 01 BALL-LINK- (COUP-SOL) n wherein:

(l) DYE is a dye radical exhibiting selective absorption in the visible spectrum and containing an acidic solubilizing group;

(2) LINK is a connecting radical selected from the group consisting of an azo radical, a mercuri radical, an oxy radical, an alkyldene radical, a thio radical, a dithio radical and an azoxy radical;

(3) COUP is a coupler radical selected from the group consisting of a S-pyrazolone coupler radical, a pyrazolotriazole coupler radical, a phenolic coupler radical and an open-chain ketomethylene coupler radical, said COUP be ing substituted in the coupling position with said LINK;

(4) BALL is a photographically inert organic ballasting radical of such molecular size and configuration as to render said coupler nondiifusible during development in said alkaline processing composition;

(5) SOL is selected from the group consisting of a hydrogen atom and an acidic solubilizing group when said color developing agent contains an acidic solubilizing group, and SOL is an acidic solubilizing group when said color developing agent is free of an acidic solubilizing group; and

(6) n is an integer of 1 to 2 when said LINK is an alkylidene radical, and n is 1 when said LINK is a radical selected from the group consisting of an azo radical, a mercuri radical, an oxy radical, a thio radical, a dithio radical and an azoxy radical;

(II) a dye image-receiving element comprising a support having thereon a light-reflecting layer comprising titanium dioxide in a binder and a dye imagereceiving layer, said element being adapted to be superposed over said blue-sensitive silver halide emi'llsion layer after exposure of said photosensitive elements; and

(III) a rupturable container containing an alkaline 14 processing composition and which is adapted to be positioned during processing of said film unit so that a compressive force applied to said container by said pressure-applying members will effect a discharge of the containers contents between said dye imagereceiving layer and said bluesensitive silver halide emulsion layer of said photosensitive element; said film unit containing an aromatic primary amino color developing agent; the improvement comprising employing zinc oxide in association with said light-reflecting layer.

11. The photographic film unit of claim 10 wherein said zinc oxide is present in said light-reflecting layer.

12. The photographic film unit of claim 11 wherein said zinc oxide is present at a concentration of from about 25 to about 500 mg./ft.

13. A reception element comprising a support having thereon:

(a) a light-reflecting layer comprising titanium dioxide dispersed in a binder, said light-reflecting layer having zinc oxide associated therewith; and

(b) a dye image-receiving layer.

14. The reception element of claim 13 which includes a pH-lowering layer between said support and said layer (a).

15. The reception element of claim 13 wherein said zinc oxide is present in said light-reflecting layer.

16. The reception element of claim 15 wherein said zinc oxide is present at a concentration of from about 25 to about 500* mg./ft.

17. The reception element of claim 13 wherein said zinc oxide is present in a layer contiguous to said lightrefiecting layer.

18. The reception element of claim 17 wherein said zinc oxide is present at a concentration of from about 25 to about 500 mg./ft.

1?. In a process of forming a transfer image comprising:

(a) imagewise-exposing a photosensitive element comprising a support having thereon at least one photosensitive silver halide emulsion layer, each said silver halide emulsion layer having associated therewith a dye image-providing material;

(b) treating the layer outermost from the support of said exposed photosensitive element with an alkaline processing composition to eifect development of each of said exposed silver halide emulsion layers;

(0) forming an imagewise distribution of diifusible dye image-providing material as a function of said imagewise exposure of each said silver halide emulsion layer; and

(d) at least a portion of each said imagewise distribution of dilfusible dye image-providing material diffusing to a dye image-receiving layer having a lightreflecting layer associated therewith comprising titanium dioxide dispersed in a binder;

the improvement comprising employing zinc oxide in association with said light-reflecting layer.

20. The process of claim 19 wherein said treatment step (b) is effected by:

(A) superposing over the layer outermost from the support of said photosensitive element said dye image-receiving layer coated on a support, said lightreflecting layer being located between said dye imagereceiving layer and its said support;

(B) positioning a rupturable container containing said alkaline processing composition between said exposed photosensitive element and said dye imagereceiving layer; and

(C) applying a compressive force to said container to effect a discharge of the containers contents between said outermost layer of said exposed photosensitive element and said dye image-receiving layer.

15 16 2-1. The process of claim 20 wherein said zinc oxide is 3,635,707 1/1972 Cole 96-3 present in said light-reflecting layer. 3,647,435 3/ 19721 Land 963 22. The process of claim 21 wherein said zinc oxide is present at a concentration of from about 25 to about 500 AV W Primary E am r 5 A T SURO PICO A r tE References Cited 5518 an mmer UNITED STATES PATENTS U.S. Cl. X.R.

3,445,228 5/ 1969 Beavers et a1. v 96--3 96-29 D, 76 C, 76 R, 84 R; l17155 

